Aluminium and Zirconium Compounds

The aryl and enol triflates 306 and 307 couple with Me3Al, Et3Al and BU3AI [136], The enol phosphate 309, derived from ketone 308, is displaced with methyl group of Me3Al using Pd catalyst in dichloroethane. Based on this reaction, 4-tert-butylcyclohexanone (308) is converted to 2-methyl-5-tert-butylcyclohexanone (311) via 310 [137], 

The alkenylzirconium compound 314 is prepared by hydrozirconation of 1-heptyne (312) with hydrozirconocene chloride (313), and reacts with alkenyl iodide to afford the 1,3-diene 315 [138]. The Zr reagent can be used even in the presence of carbonyl group, which is sensitive to A1 or Mg reagents. 

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Aluminium and zirconium compounds used in the antiperspirants also have limited levels. The safety of using antiperspirants containing some aluminium or zirconium salts has been called into question and related to skin granulomas (European Commission, SCCNFP, 1998) and also to other unconfirmed side-effects. 

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